What is the primary use of immunohistochemistry in pathology?

Immunohistochemistry is a specialized technique used in pathology to identify specific proteins within tissue sections. This method utilizes antibodies that bind to particular antigens (proteins) present in the tissues, allowing pathologists to visualize the distribution and localization of these proteins under a microscope. By utilizing this technique, it becomes possible to diagnose various diseases, including cancer, by assessing protein markers that are characteristic of specific tumor types or stages of disease.

The ability to identify and characterize proteins is crucial in determining the biological behavior of tumors, predicting prognosis, and selecting targeted therapies. The insight gained through immunohistochemistry forms an essential aspect of modern pathological diagnostics, helping to guide clinical decision-making.

The other options, while relevant to medical practices, do not represent the primary utility of immunohistochemistry. Determining blood type is a serological test unrelated to tissue analysis, measuring glucose levels pertains to biochemical assays, and counting cells refers to hematological evaluations or cytometry techniques rather than protein identification in tissues.